The Unforgiving Flowers Blossom in the Dead of Night (彼岸花の咲く夜に, Higanbana no Saku Yoru ni) is a manga written by Ryukishi07 and illustrated by Ichirō Tsunohazu. It was serialized between the May 2010 and November 2012 issues of Fujimi Shobo's Monthly Dragon Age magazine. 07th Expansion adapted the manga into a dōjin visual novel series, with the first game released on August 13, 2011 at Comiket 80 and the second on December 31, 2011 at Comiket 81.

Marie is trapped in a horrible situation. She's being constantly tormented by her classmates and regularly molested by her teacher. With nowhere else to turn, she finds herself asking for supernatural help from one of the seven demons of the seven mysteries of her school. All she desires is the death of her cruel classmates and teacher. How far will Marie be willing to go in order to achieve the murders that would free her from her living hell?

Higanbana no Saku Yoru ni takes place in an unnamed school setting and is composed of numerous self-contained short stories, each told from the perspective of a student or staff member from the school. These stories feature bullying as a major overlying theme, as each story's protagonist is depicted as being either a victim of bullying or a bully themselves. Higanbana revolves around a series of urban legends caused by supernatural beings called y?kai, each of which claims ownership of a particular "mystery" and kills anyone who tries to investigate it. There are a total of seven "mysteries" at the start of the series, with numerous y?kai fighting each other in an ongoing turf war for ownership of these mysteries, which is granted to the seven y?kai who emerge victorious in the conflict. The stories' protagonists interact with at least one of the school's resident y?kai, who force the protagonists to deal with the consequences of their actions regarding bullying.